Accession Number : AD0694511

Title :   THE CARBURIZATION OF FOUR AUSTENITIC STAINLESS STEELS.

Descriptive Note : Rept. for Jun-Dec 68,

Corporate Author : AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS

Personal Author(s) : Stanley,James K.

Report Date : 15 SEP 1969

Pagination or Media Count : 40

Abstract : Four austenitic stainless steels (AISI Types 304 (18Cr-8Ni), 316 (18Cr-8Ni + Mo), 321 (18Cr-8Ni + Ti), and 347 (18Cr-8Ni + Cb)) were carburized in a mixture of methane-hydrogen (1-1/2 vol % methane) up to 25 hr in a temperature range of 730C (1350F) to 1040C (1900F). Carburization occurrence diagrams, i.e., time and temperature at which carburization is observed, for each of the steels are given. Typical carburized structures at 100x and 500x are given. For this work, the carburized layer was considered to comprise both zones. Photographs at 500x show the complexity of the carbide-austenite zone. The carbide formed in all cases was Cr7C3. The rate of carburization, case depth versus time, is given for each of the steels at temperatures from 870C (1600F) to 1040C (1900F). The general form of the curves is parabolic. The carburization rate for titanium-bearing Type 321 is slightly different from that of the other materials. Microhardness (Knoop) traverses were made on several of the steels, and hardness gradients for each of the steels were established. (Author)

Descriptors :   (*ROCKET ENGINES, *CORROSION), (*STAINLESS STEEL, *CASE HARDENING), AUSTENITE, MICROSTRUCTURE, HARDNESS

Subject Categories : Properties of Metals and Alloys
      Rocket Engines

Distribution Statement : APPROVED FOR PUBLIC RELEASE